The present invention relates to foundation systems for supporting manufactured buildings, and more particularly, to a foundation system capable of withstanding high external forces caused by dangerous earthquakes and high winds, thus preventing damage to the home or injury to its occupants.
Several types of mobile home or manufactured building support systems are known in the prior art. Usually, such buildings are supported by light gauge metal piers, pads, or stanchions. The building is towed to the site and placed on piers aligned under the frame of the mobile home. That support system, as well as other similar support systems rely solely upon the compressional force or weight of the mobile home to hold it on the concrete pier or pad. These piers are extremely unstable when subjected to lateral or horizontal movement, and thus such systems allow shifting of the mobile home, particularly during earthquakes or high winds, whereby the mobile home moves and falls off the support. This can result in its piers piercing the flooring of the building, causing external damage both to the structure itself and utility connections. Similarly, concrete block support systems provide little protection against lateral forces.
Various other support systems have attempted to restrain the mobile home from shifting. One such system is disclosed in U.S. Pat. No. 4,214,410 which uses a plurality of stanchions connected together by a plate which would receive the wheel drum of the mobile home so that the lugs on the wheel drum could be affixed to the plate. However, many mobile homes, particularly those without wheels, cannot be supported in such a way.
Another type of support system is disclosed in U.S. Pat. No. 4,261,149 which has pedestals aligned under the support beams of the mobile home and braced in perpendicular directions. The problem with this system, and others known in the prior art, is that the system must be specially fitted to each mobile home, a time consuming and laborious task usually done at the site. Moreover, that system presumes that it will rest on a substantially level earth surface, and also fails to take into account uneven settling of the earth surface caused by the home after it has been installed onto the system.
Other types of support systems have attempted to solve the problems caused by uneven and settling earth surfaces. For example, U.S. Pat. No. 4,417,426 discloses in FIG. 6 a vertically adjustable foundation system. However, an adjustment requires disconnecting the crossbracing of the pedestal supports. Moreover, because the adjustment requires reconnecting the cross members, the vertical increments are not variable, but extremely limited. The adjustment procedure is difficult to perform at the site.
Thus, there remains a need for an effective foundation system which can withstand earthquake and high wind forces and still have sufficient adjustability to account for varying earth surfaces. Further, such system should provide automatic coordinated leveling and the integration of all components to act as a single unit. In addition, there is a need for a foundation system which can be economically manufactured off the site and which minimizes the time and effort required to install the system at the site.